Bit packer for dual tube drilling

Abstract

A bit packer for use with a string of dual concentric drill pipe, having inner and outer tubular members concentrically arranged to mate with the inner and outer pipes of the drill string to provide an annular conduit for fluid from surface to bit and a central conduit for fluid and cuttings from bit to surface, is particularly characterized by flexible packing means mounted slidably and rotatably on the outer tubular member. The packing means deform against the hole wall to seal the annular space between the outer member and the hole wall. Upper and lower ports provide fluid communication between the annular conduit and the annular space; when the packer is moved downwardly in the hole the packing means slides upwardly to close the upper port and open the lower port; when the packer is moved upwardly in the hole, the converse occurs. A milling collar is provided above the packing means.

I claim: 
     
       1. A bit packer for use with a string of dual concentric drill pipe above a bit comprising: an inner tubular member including means for providing fluid-tight interconnection with the inner pipe of said string to provide a conduit for drilling fluid and cuttings from bit to surface;   an outer tubular member arranged concentrically with said inner member and including means for providing fluid-tight interconnection with the outer pipe of said string to provide an annular conduit for drilling fluid from surface to bit;   packing means encircling said outer member and adapted to contact the hole wall and seal the annular space between the hole wall and the outer member;   bearing means for mounting said packing means rotatably with respect to said outer member; and   means for providing a flow of drilling fluid from said annular conduit to said bearing means.   
     
     
       2. A bit packer in accordance with claim 1, including a milling collar mounted on said outer member above said packing means. 
     
     
       3. A bit packer in accordance with claim 1, wherein said packing means comprises a plurality of flexible rings of diameter greater than the hole. 
     
     
       4. A packer for use with a string of dual concentric drill pipe comprising: a cylindrical body;   means defining a first passageway in said body communicating with the annular conduit between the inner and outer pipes of said string to provide a first flow path from surface to bit;   means defining a second passageway in said body communicating with the inner pipe of said string to provide a second flow path, isolated from said first flow path, to permit cuttings to be carried from the bit vicinity to surface;   means at the bottom of said body for receiving a bit;   packing means mounted rotatably on said body above said bit to seal the annular space between said body and the hole wall; and   a milling collar mounted on said body above said packing means.   
     
     
       5. A packer for use with a string of dual concentric drill pipe above a bit comprising: an inner tubular member including means for providing fluid-tight interconnection with the inner pipe of said string to provide a conduit for drilling fluid and cuttings from bit to surface;   an outer tubular member arranged concentrically with said inner member and including means for providing fluid-tight interconnection with the outer pipe of said string to provide an annular conduit for drilling fluid from surface to bit;   packing means encircling said outer member and adapted to contact the hole wall and seal the annular space between the hole wall and the outer member, said packing means being mounted rotatably with respect to said outer member; and   first port means in said outer member providing fluid communication between said annular conduit and said annular space, wherein said packing means is slidably mounted on said outer member to close said port means to fluid flow when the bit is in drilling position at the hole bottom and to open said port means when said bit is lifted up from the hole bottom.   
     
     
       6. A bit packer in accordance with claim 5, including second port means in said outer member providing fluid communication between said annular conduit and said annular space, wherein said second port means is positioned below said first port means such that slidable movement of said packing means to open said first port means will close said second port means and vice-versa. 
     
     
       7. A packer for use with a string of dual concentric drill pipe comprising: a cylindrical body;   means defining a first passageway in said body communicating with the annular conduit between the inner and outer pipes of said string to provide a first flow path from surfact to bit;   means defining a second passageway in said body communicating with the inner pipe of said string to provide a second flow path, isolated from said first flow path, to permit cuttings to be carried from the bit vicinity to surface;   packing means mounted rotatably on said body above said bit to seal the annular space between said body and the hole wall; and   port means in said body providing fluid communication between said first passageway and said annular space, wherein said packing means is slidably mounted on said body and cooperates frictionally with the hole wall to slide upwardly and downwardly on said body to respectively close and open said port means when said body is moved respectively downwardly and upwardly in said hole.   
     
     
       8. A packer for use with a string of dual concentric drill pipe comprising: a cylindrical body;   means defining a first passageway in said body communicating with the annular conduit between the inner and outer pipes of said string to provide a first flow path from surface to bit;   a second passageway in said body communicating with the inner pipe of said string to provide a second flow path, isolated from said first flow path, to permit cuttings to be carried from the bit vicinity to surface;   means at the bottom of said body for receiving a bit;   packing means mounted rotatably on said body above said bit to seal the annular space between said body and the hole wall; and   port means in said body to provide fluid communication between said annular space and said second passageway.   
     
     
       9. A bit packer in accordance with claim 8, including means for interconnecting said first passageway with a fluid motor for driving said bit. 
     
     
       10. A packer for use with a string of dual concentric drill pipe comprising: a cylindrical body;   means defining a first passageway in said body communicating with the annular conduit between the inner and outer pipes of said string to provide a first flow path from surface to bit;   means defining a second passageway in said body communicating with the inner pipe of said string to provide a second flow path, isolated from said first flow path, to permit cuttings to be carried from the bit vicinity to surface;   packing means mounted rotatably on said body above said bit to seal the annular space between said body and the hole wall; and   port means in said body providing fluid communication between said first passageway and said annular space.